private USBBroadCastReceiver mBroadcastReceiver;

     IntentFilter iFilter = new IntentFilter();
       iFilter.addAction(Intent.ACTION_MEDIA_EJECT);
       iFilter.addAction(Intent.ACTION_MEDIA_MOUNTED);
       iFilter.addAction(Intent.ACTION_MEDIA_REMOVED);
       iFilter.addAction(Intent.ACTION_MEDIA_UNMOUNTED);

       iFilter.addDataScheme("file");
       mBroadcastReceiver = new USBBroadCastReceiver();
       registerReceiver(mBroadcastReceiver, iFilter);

private class USBBroadCastReceiver extends BroadcastReceiver {
      @Override
      public void onReceive(Context context, Intent intent) {
       String action = intent.getAction();

       if (action.equals(Intent.ACTION_MEDIA_EJECT)) {

          //USB設備移除，更新UI    
       } else if (action.equals(Intent.ACTION_MEDIA_MOUNTED)) {

          //USB設備掛載，更新UI
        }
      }
 }

  //獲得掛載的USB設備的存儲空間使用情況

public static String getUSBStorage(Context context){
      // USB Storage 

      //storage/udisk為USB設備在Android設備上的掛載路徑.不同廠商的Android設備路徑不同。

      //這樣寫同樣適合于SD卡掛載。
      File path = new File("/storage/udisk");

      StatFs stat = new StatFs(path.getPath());
      long blockSize = stat.getBlockSize();
      long totalBlocks = stat.getBlockCount();
      long availableBlocks = stat.getAvailableBlocks();
      String usedSize = Formatter.formatFileSize(context, (totalBlocks-availableBlocks) * blockSize);
      String availableSize = Formatter.formatFileSize(context, availableBlocks * blockSize);
      return usedSize + " / " + availableSize;//空間:已使用/可用的
 }

try {

     //獲得外接USB輸入設備的信息
     Process p=Runtime.getRuntime().exec("cat /proc/bus/input/devices");
     BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
     String line = null;
     while((line = in.readLine())!= null){
       String deviceInfo = line.trim();

       //對獲取的每行的設備信息進行過濾，獲得自己想要的。

     }  

    } catch (Exception e) {
  // TODO: handle exception
     e.printStackTrace();
    }

I: Bus=0003 Vendor=11c0 Product=0030 Version=0110
N: Name="ACRUX USB Keyboard"
P: Phys=usb-0000:00:04.0-1.3/input1
S: Sysfs=/devices/pci0000:00/0000:00:04.0/usb1/1-1/1-1.3/1-1.3:1.1/input/input3
U: Uniq=
H: Handlers=mouse1 event3
B: PROP=0
B: EV=17
B: KEY=70000 0 0 0 0 0 0 0 0
B: REL=103
B: MSC=10